Magnetic bearing motor compressor

Abstract

A sealed induction motor for a chiller assembly is provided. The induction motor includes a stator, a rotor, and a shaft with a first end and a second end. The rotor and the shaft are configured to rotate relative to the stator. The induction motor further includes a first magnetic bearing assembly located proximate the first end of the shaft and a second magnetic bearing assembly located proximate the second end of the shaft. The first and the second magnetic bearing assemblies are configured to support the shaft. The shaft is coupled to a centrifugal compressor using a direct drive connection.

What is claimed is: 
     
       1. An induction motor for a chiller assembly, the induction motor comprising:
 a stator having a tubular shape; 
 a rotor coupled to a shaft, the rotor and the shaft configured to rotate relative to the stator; 
 a first magnetic bearing assembly configured to support the rotor; and 
 a housing configured to at least partially encapsulate the stator, the rotor, the shaft, and the first magnetic bearing assembly; 
 wherein the stator is coupled to the housing using a clearance fit configured to prevent distortion of the tubular shape, and wherein a first clearance between the housing and a motor jacket coupled to the stator is controlled such that deviations in a second clearance between the stator and the rotor do not exceed ten percent of a nominal clearance value. 
 
     
     
       2. The induction motor of  claim 1 , wherein the shaft is coupled to a centrifugal compressor, the centrifugal compressor comprising an inlet, an impeller, a diffuser, and a scroll assembly. 
     
     
       3. The induction motor of  claim 2 , wherein the shaft is configured to drive the impeller via a direct drive connection. 
     
     
       4. The induction motor of  claim 2 , wherein the first magnetic bearing assembly comprises a thrust magnetic bearing assembly. 
     
     
       5. The induction motor of  claim 4 , wherein the thrust magnetic bearing assembly is located proximate the impeller. 
     
     
       6. The induction motor of  claim 1 , wherein the induction motor further comprises a second magnetic bearing assembly and a third magnetic bearing assembly. 
     
     
       7. The induction motor of  claim 1 , wherein the centrifugal compressor utilizes a low pressure refrigerant having an operating pressure of less than 400 kPa. 
     
     
       8. The induction motor of  claim 7 , wherein the low pressure refrigerant is R1233zd. 
     
     
       9. The induction motor of  claim 1 , wherein the motor jacket is fabricated from aluminum. 
     
     
       10. An induction motor for a chiller assembly, the induction motor comprising:
 a stator having a cylindrical shape; 
 a motor jacket having a cylindrical shape, the motor jacket configured to at least partially encapsulate the stator; 
 a rotor coupled to a shaft, the rotor and the shaft configured to rotate about a central axis relative to the stator and the motor jacket; 
 a first magnetic bearing assembly configured to support the rotor; and 
 a housing configured to at least partially encapsulate the stator, the motor jacket, the rotor, the shaft, and the first magnetic bearing assembly; 
 wherein a first clearance between the housing and the motor jacket is controlled such that deviations in a second clearance between the stator and the rotor do not exceed a threshold clearance value. 
 
     
     
       11. The induction motor of  claim 10 , wherein the threshold clearance value is ten percent of a nominal clearance, wherein the nominal clearance is defined by concentric alignment of the stator and the rotor along the central axis. 
     
     
       12. The induction motor of  claim 10 , wherein the motor jacket is fabricated from aluminum. 
     
     
       13. The induction motor of  claim 10 , wherein the first magnetic bearing assembly comprises at least one of a radial magnetic bearing assembly and a thrust magnetic bearing assembly. 
     
     
       14. The induction motor of  claim 10 , further comprising a second magnetic bearing assembly and a third magnetic bearing assembly.